The present invention relates to an information reading/processing system for a recording medium on which a data pattern is formed using a fluophor and, more particularly, to an information reading/processing system for reading a data pattern formed by a fluophor on a card-like recording medium.
It is known that a light ray having a specific wavelength is emitted from a fluophor when light is incident on the fluophor. For example, when an infrared ray with a wavelength .lambda.a is produced by an infrared source and is radiated onto the fluophor, a light ray with a wavelength .lambda.b is emitted from the fluophor.
In order to optically read out the data pattern written on the recording medium, a data pattern recorded portion of the recording medium is scanned with light, and reflected light is then optically detected. When the data pattern is recorded using a fluophor, a light ray having a wavelength .lambda.b is selectively filtered, and the light reflected by the fluophor is detected, thereby effectively reading out data recorded on the recording medium.
In general, in order to excite the fluophor so as to readily read out data from the recording medium, light energy must be radiated onto the fluophor For example, a high-power LED of about 10 mW to 50 mW must be used to properly excite the fluophor. Furthermore, in order to read out data by means of the reflected light rays (corresponding to the data pattern) from the fluophor, a beam spot having a beam angle of 5.degree. (half-power width) is formed on the data pattern so as to scan the pattern with the beam. For this purpose, an LED with a convex lens is used. Alternatively, an excitation light source system must be arranged wherein a convex lens is disposed along an optical axis so as to oppose the fluophor of the LED.
The filter extracts only the exciting light waves having a wavelength .lambda.b and transmits them to a light-receiving element for reading and detecting data. Light reflected by the recording medium and incident thereon must be collimated light. For this purpose, a light guide must be disposed between the fluophor of the recording medium and the filter so as to collimate the light reflected by the fluophor which has the data pattern. The light guide comprises a special lens system which has an infinite focal length from the physical viewpoint. As a result, the information reader becomes large in size.
In the information reader wherein the data pattern of the fluophor is scanned with a beam spot and light reflected by the fluophor is read, a large scale configuration must be utilized at high cost. Furthermore, in order to accurately read out the recorded data, assembly must be performed with high precision.